Rioli put on a block on for leading teammate Jeremy Finlayson during the Power's win at Adelaide Oval on Sunday and threw out an arm which caught Ridley high.
The Bombers defender fell to the turf and had to be helped off the ground before he was substituted out of the match.
Essendon expect Ridley to miss multiple games because of concussion as a result of the off-the-ball incident.
On Monday, AFL match review officer Michael Christian graded Rioli's actions as careless conduct, severe impact and high contact.
The AFL will argue Rioli should be banned for at least three matches, and possibly more.
The 27-year-old has kicked 10 goals in eight matches in his first season with Port Adelaide following a high-profile switch from West Coast.
It came after a turbulent few years, during which Rioli served a two-year doping suspension and pleaded guilty in court to drug possession.
He will front the tribunal on Tuesday night.
Three other players will roll the dice at the tribunal as they attempt to have suspensions overturned.
Melbourne young gun Jacob van Rooyen will challenge a two-match penalty for striking, while Carlton's Nic Newman and Geelong's Brad Close will contest one-match bans.
Van Rooyen's attempted spoil in a marking contest led to Gold Coast's Charlie Ballard being taken off the field on a stretcher at Heritage Bank Stadium on Saturday night.
The 20-year-old's action was considered careless conduct, high contact and high impact.
The grading resulted in a two-match ban that cannot be reduced with an early guilty plea.
Ballard was hurt but not concussed in the final-quarter incident and is expected to play against West Coast on Friday.
Newman received a one-match ban for striking after he made contact to Lachie Neale's chin with his elbow during the Blues' loss to Brisbane at Marvel Stadium on Friday night.
Neale was given a free kick for the third-quarter incident as Brisbane players rushed to remonstrate with Newman, whose action was graded as intentional conduct, low impact and high contact.
Close was charged with rough conduct over a dangerous tackle on Adelaide's Jordan Dawson in Saturday's match at GMHBA Stadium.
Hawthorn's Tyler Brockman accepted his own one-match ban for a dangerous slinging tackle on Fremantle's Brandon Walker at Optus Stadium on Saturday night.
The Close and Brockman incidents were both assessed as careless conduct, medium impact and high contact.
Also on Monday, Rioli's Power teammate Connor Rozee was offered a $2500 fine making careless contact with an umpire.
It is Rozee's third such offence.
Nine Collingwood and Sydney players were fined for their roles in a melee during Sunday's MCG thriller.
The group included Swans small forward Tom Papley, who was charged as the instigator and can accept a $1500 fine.
North Melbourne co-captain Jy Simpkin can accept a $1000 fine for misconduct against St Kilda's Mattaes Phillipou at Marvel Stadium on Sunday.
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